In addition to the ongoing clinical trial, we plan to continue our efforts to isolate and characterize the protective factor in J5 antiserum and to refine a simple J5 antibody assay which employs radiolabelled endotoxin. We will also continue to evaluate various methods of subcutaneous immunization in rabbits in an attempt to enhance the protective potency of J5 antiserum. BIBLIOGRAPHIC REFERENCES: Ziegler, E.J., McCutchan, J.A., Douglas, H., and Braude, A.I. Prevention of lethal Pseudomonas bacteremia with epimerase-deficient E. coli antiserum. Trans. Ass. Physicians, 88: 101-108, 1975. Braude, A.I., Ziegler, E.J., and Douglas, H. Protective properties of antisera to R-Core. Microbiology 1976, ed. D. Slessinger, American Society for Microbiology, Washington, D.C., Press.